Consistency controlling mechanism for concrete mixers



April 18, 1933. p YQHE 1,904,025

CONSISTENGY CONTROLLING MECHANISM FOR CONCRETE MIxERs ori inal Filed April 7, 1928 s Sheets-Sheet 1 gwwntoa,

dtavuwtp April 18, 1933. P. P. YOHE 1,904,025

CONSISTENCY CONTROLLING HECHAHISII FOR CONCRETE IIXERS Original Filed April 7, 1928 3 Sheets-Sheet 3 BB Yoke.

Patented Apr. 18, 1933 UNITED STATES PATENT OFFICE PERRY P. YOHE, OF NORTH HOLLYWOOD, CALIFORNIA, ASSIGNOB T KOEHBIN'G' COMPANY, OFMILWAUKEE, WISCONSIN, A CORPORATION CONSISTENCY conrnonnmc mncrmmsm FOB concnmn mamas Continuation of application Serial No. 268,215, filed April 7, 1928. This application flled llial'ch 1, 198;).

Serial 1510. 432,434.

This application is a' continuation of my application Serial No. 268,215, filed April 7th, 1928, for concrete mixer, and relates more particularly to the method and apparatus for determining with accuracy the consistency of concrete as it is being mixed in a concrete mixing machine.

In the art of concrete engineering, it is a well known fact that the strength of conlo crete primarily depends upon a certain proper ratio of water and cement during the initial mixing thereof.

Concrete when mixed with a minimum amount of water, said amount being just sufficient to make the mass workable, acquires a much greater strength than concrete when mixed witha greater quantity of water, it

being assumed, of course, that the quality and quantity of the other ingredients are the same.

In concrete mixing apparatuses which are used today, it is practically impossible to determine with any degree of accuracy the amount of water contained in the mix. The

reason for this is that all of the aggregates which are used contain a certain amount of water which is commonly known as the moisture content, and this moisture content is extremely variable, not only depending upon the atmospheric conditions at the time the materials are used but also upon the condition of the materials at the time they are delivered on the job. Extremely accurate measuring devices are being used today for predetermining the quantity of Water which goes into the mix of a particular batch of cement, but from the above, it can be readily observed that even though this quantity of water is known, when the material is introduced into the mixing machine, itcontains a variable quantity of water which is unknown, and, therefore, the amount of Water contained in the mix is necessarily variable and unknown.

An object of my invention is to remedy the above difficulties just pointed out by deter- Another object of my invention is to provide an apparatus for supplying to a quantity of cement as it is being mixed in the concrete mixing machine, a predetermined quantity of water, and to vary that quantity of water by mechanical means directly in proportion to the -.quantity of water 'previthe mix to the desired consistency, subsequently supplying to the mix the desired quantity, and mixing the aggregates, cement v and water for a predetermined period.

. A still further object of my invention tointroduce into a mixing drum a certain quantity of cement and aggregates, adding thereto suflicient water to make a thick workable mass, rotating the drum to cause a mixing action, utilizing the resistance to rota tion of the drum which is caused by the consistency of the mixture to predetermine the quantity of water to be subsequently delivered to the drum to bring the mix to the desired consistency, permitting the mass to mix a predetermined time, and adding the additional predetermined quantity of water to bring the mix to the desired consistency.

Other and further objects and advantages of the invention will be hereinafter set forth and the novel features thereof defined by the appended claims.

In the.,drawings:

Fig. 1 is a diagrammatic elevation of a concrete paving machine, showing my invention applied thereto;

Fig. 2 is an enlarged elevation of the charging end of a concrete mixing drum, disclosing the yieldable power drive therefor,

the primary water supply means therefor being-shown in section;-

Fig. 3 is a side ele ationof a mixing drum, having my improved consistency determining and water supplying apparatus applied thereto;

-view of a portion of the shiftable ringgear,

-. showing the resilientdriving connection for the mixing drum;

Fig. 8 is a sectional view onjline 8-8 of Fig. 9 isga detaili'view of a conventional snap-over mechanism suchas may be used for actuating the" water control valves; and

Fig. 10 is ad'e'tail sectional view of thea stand pipe associated withthe supplemental cates an engine for furnishing .operate the several parts-of .t

water supply means of Fig. 1. Like reference haracters refer to like parts in the several figures of the drawings.

Referringto Fig.1, the numeral 1 indithe pbwer to e mixinguna chine in which 2 illustrates the charging-skip which is 'shiftable to receiving and charging positions,as shown in full and dotted lines respectively. a

The aggregates-to be mixed are placed in i this skip, together with the cement, after which the skip is elevated to the dotted line position to discharge its contents into the mixing drum-3. At the endof the mixing period, the discharge chute 5 is tilted to discharging position which directs the aggrebe emptied.

gates from the mixing drum into the distributionbucket 6. The bucket is movable along the boom to the desired place of deposit and the-door in the lower portion of the bucket is opened to allow to bucket to I The aforementioned description relates to the conventional type of paving machine to" which my invention is applied.

Disclosed above the mixing drum 3, and in a position to be actuated by the skip during the. charging action thereof, is a shiftable rod 4. This rod has ivoted thereto link members 4a and 4b, the rec ends of which are connected to the valve members 8 and 7 reas the primary water tank, and the mixspectively. To provide for instantaneous, actuation of the valves 7 and 8, I may provide a conventional snap-over mechanism positioned intermediate the-valves 7 and 8 and thelink members 40 and 47). A type of this snapvover mechanism is disclosed in Fig. 9 and will later be described.

The-valve 7 establishes communication between the water tank 9, hereafter referred to ing drum, while the valve 8 establishes communication between any suitable source of sup ly for furnishing water to" the rimary ta 9 and said tank. It will be ere observed that the valves 7 and 8 are set in opposition positions, thatis, one valve is open when the other is closed, and vice versa. The primary water tank 9 is designed to supply a predetermined quantity bf water to the mixing drum 3, as controlled by the valves 10, 11, 12 and 13. Referring to Fig. 2, it will be observed that,,depending upon which of the valves jllSt referred to is open, the water contained in the tank 9 will be discharged at the proper time through the pipes 17 into the mixing drum until the water levelreaches the particular opening as controlled by the valve, whereupon further discharge wlll be. prevented. With the valves? and 8 in the osition shown in Fig. 2, the tank 9 will be lled from the water supply until the water level actuates the float valve 14 which is disposed in the air vent 15. The float member 16 of the float valve 14 will be then carried upwardly and cause'the air vent to be closed,

thus preventing the admission of'additional water into the tank 9.

The rod 4 is threaded at 20a and has positioned thereon adjacent its end a clutch member 19; This clutch member is internally threaded, as indicated at 20. Freely rotatable on the rod 4-is a sprocket wheel 21 recessed at 22 to receive the clutch teeth 23-of the cylindrical clutch member 19. A com-.

presslon spring 24 and washers 25 are dis posed between the clutch member 19 and the extreme end of the rod 4 to 'maintain the clutch member 19 normally in interlocking engagement with the sprocket wheel 21. The sprocket wheel 21 is driven through the chain 28 by a friction disc 26 said disc being secured to a rotatable shaft which is, in turn, suspended from the frame of the mixer, and which has fixed thereto a sprocket 27 carrying the driving sprocket chain 28.

Disposed on the-mixing drum 3 in of the friction disc 26 is a cooperating friction block 29 which causes intermittent rotation of the disc 26 as'the drum 3 rotates.

The drum 3 carries thereon ashiftable rin gear or sprocket 32. A sprocket 30 disposed on the driving shaft 301; receives the drum drive chain which, in turn, engages the ring gear sprocket 32.

The mountlng ofthering gear sprocket 32 I to permit relatlve movement thereof with respect to the mixing drum 3, is clearly seen in Figs. 3, 4, 5 and 7. The ring gear sprocket is slotted at 35 to receive the guide studs 33 which may be secured in any suitable man'- ner, having thereon the washers 34. Disposed on the mixing drum at spaced inter- .vals are the compression spring supports 38. Projecting from the ring gear sprocket assembly 32 are extensions 37. Compression springs 36 are positioned between the supports 38 and the extensions 37 v of the ring gear to normally exert pressure tending to rotate the ring gear with respect to the mix- Q i the path ing drum to the position shown in Fig. 7 with the studs 33 engaging the ends of the slots 35. Projectin laterally from the ring gear assembly are the cam members 39.

Disposed on the mixing drum 3 in parallel spaced relation to the ring gear sprocket 32 is a laterally shiftable annular flanged ring 43. The flanged ring carries a plurality of actuating rods 41 which project toward the cams 39 carried by the ring gear sprocket 32. The rods 41 are slidably positioned in brackets 42 carried by the mixing drum 3 and are urged toward the ring gear sprocket 32 by the springs 45 which engage the brackets 42 and the collars 41a carried by the rods 41. Rollers 40 are pivotally secured to the ends of the rods 41 to provide an anti-frictional contact between the aforementioned rods and the cam members 39.

The radial flange of the ring 43 lies to the right and adjacent the arm 44 fixed to a rod 46 slidably carried in brackets 47 on the frame of the mixing machine. This rod 46 is clearly seen in Fig. 3 of the drawings and constitutes part of the setting mechanism for the secondary water supply device which will hereinafter be described. A spring 68 is disposed between one end of the rod 46 and one of the brackets 47, maintaining the rod with its arm 44 resting against the flange of the ring 43. Pivoted to a collar which is fixed to the rod 46 is a link 48 which is, in turn, pivoted to the gear segment 49. A pinion 52 meshes at one side with the gear segment 49 at the other side with a vertically disposed rack 53 which is carried by a rod 54 disposed for vertical movement in thebrackets 55. The rod 54 constitutes a movable sup port for the four-way casting 56. The four way casting 56 is hollow, having projecting upwardly therefrom the vertical stand pipe 56a containing a float valve 56?), and is provided with flexible conduits 57 and 58. These conduits are connected to the secondary water tank 61 which isrigidly carried by the framework of the mixing machine in any suitable manner, such as by the brackets 62. A float operated vent valve 65 is disposed in the tank 61 to be closed when the water level reaches the top of the tank. Discharge and intake conduits 59 and 60 also communicate with the four-way casting 56 and include flexible portions 59a and 60a. Disposed in the conduit 59 is the control valve 67, while a similar control valve 66 is disposed in the inlet conduit 60.

These valves may be also provided thereto, as shown.

mechanism for the valves 66 and 67, as well as the valves 7 and 8. The levers 63 connect the valves 66 and 67 with the rod 4 so that as the rod is moved in one direction the snapover mechanisms for the valves 66 and 67 operate to shift the valves in one of their alternate positions, while when the rod 4 is .moved in the other direction, the valves will be shifted to the other alternate position.

It should be here observed that the vertical disposition of the casting 56, as determined by the adjust-ment of the rack 53, will of the'pipe 59 leading into the pipe 17 which enters the mixing drum 3. As shown in Fig. 3, the parts are at rest with the casting 56 disposed above the tank 61, but it should be here noted. that when the cement is being mixed in the drum 3, the resistance of this mass to rotation of the drum will cause a relative shifting of the ring gear 32 and cams 39 carried thereby which will actuate the rods 41 to move the annular flanged ring 43 to the left. As the flange is moved to the left, the rod 46, through its link connection 48, will shift the gear segment 49 in an anticlockwise direction, causing the casting to be lowered to some predetermined point below the top of the tank 61. This point is, of

course, dependent upon the relative movement of the ring gear 32 with respect to the drum 3 incident to the resistance to rotation as oifered-by the consistency of the mass contained in the drum 3.

Referring again to Figs. 3, 4, 5 and 6, it should be noted that the cylindrical clutch member 19 constitutes a sort of timing mechanism for the valves 7, 8, 66 and 67. This mechanism will now be described in detail:

As the drum 3 rotates, the friction block 29 engages the friction disc 26 to rotate the same an increment of movement for each revolution of the mixing drum 3. The rotation of the friction disc 26 actuates the sprocket 27 and through the chain 28 rotates the sprocket wheel 32. When the cylindrical clutch member 19 is in the position shown in Fig. 6, this member is also rotated as the drum rotates, since the spring 24 causes the clutch teeth 22 to engage the recesses 23 in the rotating sprocket wheel 21, the threaded portion 20 of the cylindrical clutch member maintaining the rod 4 in unthreaded relation It should, be here observed that when the rod 4 is moved inwardly or to the left from the position shown in Figs. 3 and 5, the threaded portion on the rod 4 will engage and force the cylindrical clutch member 19 away from the Sprocket wheel 21, whereupon the spring 24 will become efiective to cause the clutch member 19 5 to be rotated by the screw threads a carried by the rod 4 as the clutch member screws itself on the said threads. This action takes place as the skip 2 is raised to charge the mixing drum 3. Simultaneously with the movement to the left of the rod 4, as above described, the valves 7 8, 66 and 67 are actulat'ed. The valve 7 is shifted from closed position to open position to permit the primary water tank 9 to discharge its co tents into the mixing drum, While the valve 8 is simultaneously shifted to close the ommunication between the primary tank an the supply line 8a. The valve 66 is also simultane- 'ously opened to permit water to flow from the intake supply pipe into the secondary water tank.61, while .the valve 67 is closed to prevent the escape of water from the secondary tank-into the pipe 17. It will be here observed that as the primary tank 9 is discharging, the secondary tank 61 is filling.

Due to the intermittent rotation of the sprocket wheel 21, the cylindrical clutch member 19 will be rotated thereby when the skip 2 is lowered to permit the. spring 40 to move the rod 4 to a position where the clutch teeth 22, carried by thecylindricalclutch member, enga the recesses 23 inthe sprocket wheel 21. the cylindrical clutch member 19 rotates, the threads 20a on the rod 4 will gradually be unscrewedfrom the threads 20 on the cylindrical clutch member 19, which produces agradual movement to the right of the rod 4. During the movement of the rod 4 to the initial position, as shown in Figs. 3, 4 and 5, the valves 7, 8,66 and 67 will again be actuated to establlsh communication between the supply line 8a and the primary water tank 9 and establish communication between the secondary water tank 61' and the discharge conduit 59 which leads into the pipe 17 and from there into the mixing drum. The other two valves 7 and '66 are closed, which prevents any additional Water from being discharged from the primary tafik 9 as this tank is being filled, and also prevents any additional water from being supplied to the. secondarytank 61 as this tank is being discharged. It should be further observed that a predetermined period of time will elapse between the movement of the rod from the left hand position thereof due to the impingement ofthe skip thereagainst, to the final restoring of the rod' incident to the rotation of the cylindrical clutch member 19, and this periodarepresefits the interval of time between the discharge of the water from the primary w%ter ta'nk until the discharge of the water fr m the secondary water tank. The reason for this is as follows:

As the skip is elevated to charge the drum with aggregates and cement to be mixed, the rod when moved inwardly, or to the left, discharges the contents of the primary water tank to provide an initial mixing of the aggregates and waterto form a preliminary mixture, so to speak, to determine the amount of water necessary for the final mixture.

The resistance to rotation 'of the drum by this preliminary mixture causes the secondary water measuring device to be adjusted. and as the rod 4 is slowly screwed to the left by the threads 20 of the cylindrical clutch member 19, the valves 7, 8, 66 and'67 will, after a certain period of time, be shifted to permit this secondary quantity of Water to be discharged into the mixing drum.

connected to a lever 78 freely pivoted to the stem of the valve. A spring 7 9 is connected between the end of the lever 78 and the end of the lever fastened to the valve stem. As the lever 78 is shifted to dotted line posibeyond the pivotal center of the levers 75 and 78 to cause the lever 75 for actuating the valve to swing rapidly to the dotted line position shown in this figure.

Describing the complete cycle of operation of my invention, it should first be understood that the primary tank 9 is filled with water and the valves 10 to 13 properly adjusted to deliver just the sufiicient quantity of water into the mixing drum to provide a thick but workable mix, the skip having been loaded with the desired mixture of aggregates and cement. v The operator now throws in the skip hoisttlutch, not shown, to elevate the 'tion shown in this figure, the spring will pass skip tothe charging position shown in dotted lines in Fig. 1 of the drawings. As the skip reaches this position, it impinges the rod 4,

forcing the same to the left.

Referring now to Figs. 3 to 5, it will be observed that as the rod 4 moves to the left,

the valves 7 and 8' will be actuated to interrupt the communication between the supply and the primary tank 9 and establish com-. munication between said tank and the mix-'- I 'ined quany 'tity from the tank into said drum. -As the ing drum to discharge a predete rod 4 is moved to the left, the spring4cis compressed and the clutch member 19 dis:

engaged from the sprocket wheel 21. This causes the spring 24 to screw theclutch member 19 on the threads 20 of the rod 4.

The valve members 66 anti .67 are also acgradually moved back to its initial position,

as shown in Fig. 4 of the drawings, but previous to the complete restoration of the rod 4, the mixture of aggregates and water within the drum 3 causes a certain amount of resistance to rotation of the drum to be eifected.

Since the drum is being rotated by the ring gear 32, which is yieldably disposed for relative movement on the drum, this ring'gear will be shifted to a degree in direct ratio to the relative consistency of the mixture within the drum.

The shifting of the ring gear 32 adjusts the cams 39 which," in turn, move the annular flanged ring 43-to the left, causing the rod 46 to actuate the segment 49. Movement of the segment 49 rotates the pinion 52, lowering the rack 53, which causes the casting 56 to be positioned below the level of the water in the now filled supplemental tank 61. The rod 4, as it is being slowly moved to the right, now actuates the valves 66, 67, 7 and 8 to restore them to their original positions, namely, to establish communication between the supplemental tank 61 and the mixing drum 3 and cut off the water supply to this tank, while the valves 7 and 8 close the communication between the primary tank 9 and drum and establish communication between the supply 8a and the tank.

Water will now flow out of the tank 61 into the casting 56 and down into the mixing drum 17 .until the water level drops below the position of the casting 56, as determined by the consistency of the preliminary mixture within the drum 3. When the water level within-the tank 61 drops below that of the level of the casting 56, air will be admitted and, therefore, cannot efi'ect a subsequent ad-' justment of the casting 56 untilafter the predetermined quantity of water has been discharged from the secondary water tank 61. After the secondary quantity of water has been added to the mixture, the mixing of the aggregates in the drum may be continued through a desired period of time, after which the drum is discharged and it is then ready for another charge of aggregates, whereupon the cycle is repeated. 7

While the specific details of construction have been herein shown and described, the invention is not confined thereto as'changes and alterations may be made without departing from the spirit thereof ,as defined by the appended claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is: v

.1. The method of predetermining the consistency of a mixture of cement, aggregates and water which consists of placing the said elements in a moving vessel, utilizing the resistance to movement of the vessel offered by the mixture therein to predetermine thequantity of Water to bring the mixture to a known consistency, and supplying said quantit-y of water to the mixture as determined by the said resistance.

2. In a concrete mixing apparatus, the com-, bination of a mixer, secondary water supply means for supplying a variable quantity of water to the mixer, and consistency determining means including a part connected with said mixer and movable according to the resistance to the movement of the mixer, and a connection between such part and said water supply means to actuate the latter and thus control the quantity of Water to be delivered therefrom by said consistency determining means.

3. In a concrete mixing machine, a mixing drum, means for rotatably supporting said drum, water supply means, means for driving said drum, and a resilient driving connection between said drum and said driving means, .together with operating connections from the driving connection to the water supply to control admission of water to the drum and thus control the consistency of a mixture of cement, aggregates and water when mixed within the drum incident to relative movement between the resilient driving connection and the drum.

4. In a concrete mixing machine, a support,

amixing drum rotatably carried thereby,

water supply means for supplying water to said drum to produce a preliminary mixture when cement and aggregates are placed within the drum, means for determining the consistency of the preliminary mix, means operable by the consistency determining means to measure a predetermined quantity of water to be later supplied to the mixture to reduce the consistency of the mixture to a predetermined degree. and control means for discharging said predetermined quantit-y of water into the preliminary mixture, said control means being operable after a predetermined lapse of time.

5. In a concrete mixing machine, a; mixing vessel, a charging device therefor, a primary water supply means for suppl ing a measured quantity of water into sai mixing vessel to produce a preliminary mixture when aggregates and cement are contained therein, a secondary water sufpply means tosupply a va-rlable quantity 0 water tosaid vessel, means for determining the consistency of the preliminary mixture within the vessel, said means bein adapted to adjust the secondary water supp y means, means operable by the charging device to discharge the primary water supply means, and a time controlled discharge means for discharging said secondary water supply means adapted to be set into operatmhby said charging device.

6. In a concrete machine, a mixing drum, a charging skip or introdncing dry aggregates of a concrete mixture into the drum, a. water tank for introducing a predetermined quantity of waterinto the drum to form-a prelimmarymixture, means operable by the charging skip'to cause discharge of sa1d tank, means to measure a variable additional quantity of. water to be later supplied to said mixture to bring said mixture to a predetermined consistency, and time controlled means for discharging said variable additional quantity of water after a prede e termined time, said means being initiated into operation incident to niovementpf the charg-.

In concrete mixing machines}; -al*-mixing drum, power means for rotatingthe drum, a yieldable drive connection between said power means and said drum, means opposing sa1d yielding action, and means forsupplying a predetermined-quantity of water to sa1d drum variable in accordance'with the degree charging skip.

' said drum with an admixture having an unof movement between thedrum and said yieldable drive means.

8. In a concrete machine, a rotatable mixing drum, a charging skip for introducing aggregates and cement into the drum to be mixed thereby, water supply means for supplying mixing water to the aggregates within the drum, power means for actuat' g said mixing drum and said charging ski a timing device for causing said water su ply means to discharge into said mixing rum after a predetermined lapse of time, and

means for settingsaid timing device into operation incident to charging action of the 9. In a mixing machine, a drum, water and aggregate supply means 'ior charging known. water content, shiftable consistency determining-means for determining the water content of said admixture when mixed by the drum, and supplemental water measuring means associated with and controlled by the .eonsistency determining means and. operable 7 the moisture .uptov nq 9 to supplya predetermined quantity of water to the admixture within the drum tobring 10 In a concrete mixing machine, a mix-. 1ng device, driving means for ctuating the m'ixing dev'ice,, a yieldable dri e connection between the driving means and the mixing device, resilient means to resist movement therebetween, a water measuring device for supplying variable quantities of water to the mixing device, and a connection between the water measuring device and the yieldable drive connection to cause the water measuring device to be set to deliver a certain predetermined quantity of water to the mixing device ating the mixin device, a supplemental water. tank for supp ying an additional quantity of water to the mixing device, valvemeans associated with the supplemental tank, power means for operating the said secondary tank valve to discharge" the same, and a timing device associated with said power means to;

being initiated into operation incident to charging action of the charging skip.

12. .In a concrete mixing machine, a mixing render the same operative, said timin device device and support therefor, primary and secvondary water supply means for supplying water to said mixing drum, a control member associated with said water supply means movable in one direction todischarge water from one of said water supply means and movable in another direction to discharge water from another of said water supply means, a measuring device associatedwith one of said water supply means, a yieldable power driving connection for the mixing device, and an operatin g connection between said yieldable power driving connection and said measuring devlce.

- 13, In a concrete mixing machine, a mix ing device and support therefor, a charging device carried by the support for introducing aggreg tes and cement to be mixed within the mixing device, primary and secondary water supply means for supplying water to the mixing device, a measuring device associated with said secondary water supply means for varying the quantity of water delivered therefrom, means carried by the mixer support for alternately operating said water supply means to discharge the same, said lastsnamed means being operable in one direction incident to charging action of the charging device to discharge the primary water supply means and operable in another direction incident to mixing action of the mixing device to discharge the secondary Water supply means, y.ieldab1e drive means for the mixing device, and a connection between the yieldable drive means and the secondary water measuring device for varying the quantity of waterto be delivered therei from incident to relative movement of the yieldable drive means and the mixing device.

14. The method of mixing concrete which comprises introducing into a mixing drum a quantity of cement and aggregates, adding thereto. suflicient Water to make a thick but workable mixture", rotating the drum, predetermining from the resistance to rotation of the drum arising from theconsistency of the mix within the drum the quantity of water necessary to bring the mix to the desired final consistency, supplying to the mix this determined quantity of water, and mixing the aggregates, cement and water for a predetermined period of time; p 25 The method of mixing concrete which comprises introducing into a mixing drum a quantity of cement and aggregates, adding thereto sufiicient water to make a thick but workable mixture, rotating the drum to produce a mixing action, predetermining from the resistance to rotation of the drum set up by the consistency of the mass the quantity of water to be added to the mixture to bring it to the proper final consistency adding the predetermined quantity of Water, and mixing the mass for a period of time, after adding the said additional predetermined quantity of Water to bring the mix to the desired consistency.

In testimony whereof I aflix my signature.

PERRY P. YOHE. 

